Hacktoberfest 2026: los issues que los mantenedores marcaron para octubre, abiertos y aptos para principiantes. Explorar issues de Hacktoberfest

Concurrency: "messages copy" is false for buffer, text_builder and closures — shared by reference through send and thread_join, with a real data race between sender and receiver

Cerrado
  • ¿Algo no está bien?
#1,148 0 comentarios 0 reacciones 0 asignados Ver en GitHub

Los mantenedores suelen responder en 1 día

Nadie ha tomado este issue todavía.

Evaluación

Dificultad
5/5
Tiempo estimado
Más de una semana
Aptitud para principiantes
35/100
Tipo de issue
Error
Claridad
Bastante claro
Estado de actividad
Activo
Stack tecnológico
c
Área
distributed-systems

Línea de trabajo

Run the probe files under ~/src/wt/briefs/conc-review/probes-{A,B,C}/ and reproduce the race with TSan. Read chan_clone_rec in src/eigenscript.c:2235-2308, its send/thread_entry callers, and the buffer operations in builtins_buf.c:116-148. Done means the reported sharing and race are resolved, with the aliasing, depth-cutoff, and closure behavior documented in docs/CONCURRENCY.md.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

area:concurrency kind:silent-wrong

Found by the 2026-09-14 whole-runtime concurrency review (three independent reviewers, every finding below reproduced by execution on main @ a18deac unless marked reading). Probe files live in ~/src/wt/briefs/conc-review/probes-{A,B,C}/.

docs/CONCURRENCY.md: "A value sent through a channel, or returned through thread_join, is COPIED … share-nothing". chan_clone_rec (src/eigenscript.c:2302-2308) shares VAL_FN/VAL_BUILTIN/VAL_BUFFER/VAL_TEXT_BUILDER/VAL_JSON_RAW by refcount (used by send :4711, thread_entry :4484, task_spawn :4940). Only a C comment says so.

Observed

c is channel of 4
b is buffer of 4
buf_set of [b, 0, 1.5]
send of [c, b]
buf_set of [b, 0, 99.0]
got is recv of c
print of f"buffer recv[0] after post-send mutation (expect 1.5): {buf_get of [got, 0]}"
tb is text_builder_new of []
text_builder_append of [tb, "before"]
send of [c, tb]
text_builder_append of [tb, "+AFTER"]
got2 is recv of c
print of f"text_builder recv (expect 'before'): {text_builder_to_string of got2}"

buffer recv[0] after post-send mutation (expect 1.5): 99
text_builder recv (expect 'before'): before+AFTER
dict.buffer recv[0] (expect 99 if copied at send): -7      # nested in a dict: same

A closure sent inside a dict still mutates the sender's captured list (101) while the sibling list in the same dict was copied ([0]). With the receiver reading while the sender writes, TSan reports the data race the doc promises cannot exist: builtin_buf_set builtins_buf.c:148 (main) vs builtin_buf_get :116 (T1). Note also that copies split internal aliasing (a joined [d, inner] with d.xs IS inner comes back as two independent lists) and the depth-64 cutoff in chan_clone_rec :2257 falls back to sharing (reading).

Fix direction

memcpy-clone buffers and text builders in chan_clone_rec (they are flat); document that functions are shared by reference and what that implies for their captured state (with the :2235-2236 caveat); document the aliasing split and the depth cutoff, or make the clone alias-preserving.

Lenguaje dominante
C
Estrellas
3
Forks
7
Merge medio
8 h 41 min
PR fusionados (30 d)
254

Preparar el entorno

Abrir en Codespaces

Inicia el contenedor de desarrollo del proyecto en tu navegador, con tu propia cuenta de GitHub.

Primeros pasos

  1. Lee el issue completo y luego la guía de contribución del proyecto.
  2. Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
  3. Haz un fork del repositorio y trabaja en una rama.
  4. Abre un pull request que haga referencia al número del issue.

Más de InauguralSystems/EigenScript

Todos los issues de InauguralSystems/EigenScript

Issues similares

Más issues de C

Recibe los nuevos issues en tu correo

Un resumen breve de issues de GitHub para principiantes.